Isotopes

• What is the main topic of today's video?

  A review of the atom in chemistry
• What does the nucleus of an atom contain?

  Protons and neutrons
• What charge do protons have?

  Positive charge
• What is the relative mass of protons and neutrons?

  One
• How much smaller are electrons compared to protons or neutrons?

  About two thousand times smaller
• What does each box in the periodic table represent?

  A particular element
• What is the elemental symbol for lithium?

  Li
• What does the atomic number indicate?

  The number of protons in an atom
• Why is the atomic number important?

  It determines the element's identity
• What is the mass number of lithium?

  Seven
• How is the mass number calculated?

  By adding protons and neutrons
• How many electrons does lithium have?

  Three electrons
• What are isotopes?

  Atoms with the same protons but different neutrons
• What are the isotopes of lithium mentioned?

  Lithium-6, Lithium-7, Lithium-8
• What is the stability of isotopes?

  Only one or two are stable
• What happens to unstable isotopes?

  They decay into other elements
• What is radioactive decay?

  The process of unstable isotopes emitting radiation
• How are electrons arranged in an atom?

  In energy levels called shells
• What happens when electrons gain energy?

  They can jump to a higher energy level
• What is an excited electron?

  An electron that has gained energy
• What provides the energy for an electron to jump levels?

  Electromagnetic radiation
• What happens after an electron jumps to a higher energy level?

  It falls back and re-emits energy
• What is ionization?

  When an electron leaves the atom
• What charge does an atom have after ionization?

  A positive charge
• What does ionizing radiation do?

  Knocks electrons off atoms
• What are the key components of an atom?

  • Nucleus: contains protons and neutrons
  • Protons: positively charged, mass of one
  • Neutrons: neutral, mass of one
  • Electrons: negatively charged, much smaller than protons/neutrons
• What information is found in a periodic table box?

  • Elemental symbol
  • Atomic number (number of protons)
  • Mass number (total of protons and neutrons)
• What is the process of radioactive decay?

  • Unstable isotopes emit radiation
  • Can emit alpha, beta, or gamma radiation
  • May emit neutrons
• How do electrons behave in energy levels?

  • Arranged in shells
  • Can jump to higher levels when energized
  • Fall back and re-emit energy
• What happens during ionization?

  • An outer electron absorbs enough energy
  • Leaves the atom, creating a positive ion
  • Ionizing radiation can cause this effect